Kuwait's Emir Sheikh Sabah al-Ahmad Al-Sabah opened an annual summit of wealthy Gulf states on Tuesday with a call for an end to the "human catastrophe" in Syria.
Sheikh Sabah, who gave a share of the spotlight at the Gulf Cooperation Council summit to the head of Syria's main opposition bloc, also condemned the United Nations for failing to halt the 33-month conflict.
"The human catastrophe is still ongoing in Syria which calls on us to double efforts and work with the international community, especially the UN Security Council which has remained unable to put an end to this human tragedy," said the emir.
He issued the plea as National Coalition president Ahmad Jarba appealed for urgent help for the Syrian opposition and for civilians.
"The Syrian people need you today to tell the whole world that the Syrian regime will have no future in the country," said Jarba, who also thanked Kuwait for launching an "aid fund" without providing any details.
Jarba accused President Bashar al-Assad's regime of "supplying arms" to the Al-Qaeda-linked Islamic State in Iraq and Levant (ISIL) in a bid to defeat the revolution.
Jarba reiterated that the opposition had agreed to attend next month's Geneva 2 peace conference under conditions including that Assad plays no role in any transitional government.
During the two-day summit, leaders are due to discuss boosting economic integration, military and security coordination in addition to upgrading the GCC into a confederation, and ties with Iran.
Only three leaders are attending, the rulers of Qatar, Bahrain and host country Kuwait.
The Saudi crown prince is representing the ailing King Abdullah, while Oman is represented by the deputy premier and the United Arab Emirates by its vice-president and prime minister.
Ties between Sunni-ruled GCC states and neighbouring Shiite Iran have come to the foreground since a landmark deal was reached last month between Tehran and world powers over its disputed nuclear programme.
Iran's Foreign Minister Mohammad Javad Zarif last week toured four Gulf countries, but not Saudi Arabia nor Bahrain.
Zarif tried to assure the Gulf states the nuclear deal was not at their expense, and called for a new page in relations, although Saudi Arabia in particular appears to remain sceptical.
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In his speech, Sheikh Sabah said the Gulf states had "expressed their satisfaction with the interim Geneva deal... hoping it would succeed and lead to an everlasting agreement that would keep tension away from the region".
This year's summit is being staged amid differences over a Saudi proposal to upgrade the GCC into a confederation.
At the weekend, Oman threatened to pull out of the loose alliance if a union was announced, while Saudi Arabia, solidly backed by Bahrain, has insisted it is time to move ahead.
'Give people more power'
Kuwait's State Minister for Cabinet Affairs Sheikh Mohammad Abdullah Al-Sabah told reporters talks over the union were ongoing.
"When consensus is reached, a special summit will convene in Riyadh to make the announcement," he said, ruling out a major declaration at the Kuwait meeting.
Details on the confederation proposed by the Saudi king in 2011 have not been disclosed.
"Oman does not want to be a part of any measure that might be seen as directed against Iran," said Emirati political analyst Abdulkhaleq Abdullah.
Muscat enjoys good relations with Tehran and might be distancing itself from a union led by heavyweight Saudi Arabia, which sees Tehran as a regional rival.
Kuwait's foreign ministry undersecretary Khaled al-Jarallah said the summit would approve the establishment of a unified GCC military command.
But activists called on the Gulf monarchies to give their people more power, as well as a role in managing oil wealth.
"It is time that the Gulf people participated in the running of their affairs... through the establishment of true parliaments," said a letter by the Gulf Forum for Civil Societies to the Gulf summit.
GCC states, which have a combined gross domestic product of $1.6 trillion, will also assess their economic integration projects, especially a slow-moving customs union and plans for a common currency.
On the back of high oil prices, the six nations, with a combined population of 47 million, almost half of them foreigners, have accumulated financial assets worth $2 trillion. This is expected to grow to $2.4 trillion in 2014.